Process and apparatus for filling and for removing contaminants from the flotation chamber of a flotation instrument



June 22, 1965 J. F. ROBINSON 3,190,321

PROCESS AND APPARATUS FOR FILLING AND FOR REMOVING CONTAMINANTS FROM THE FLOTATION CHAMBER OF A FLOTATION INSTRUMENT Filed July 5, 1961 TO ATMOS FIGJ INVENTOR. JOHN F. ROBINSON ATTORNEY chemically neutral. neutralized by repetitive contact with the circulating ap- United States Patent PROCESS AND APPARATUS FOR FILLING AND FOR REMOVING CONTAMINANTS FROM THE FLOTATHON CHAMBER OF A FLOTATION IN- STRUMENT John F. Robinson, La Canada, Calif., assignor to North American Aviation, Inc. Filed July 3, 1961, Ser. No. 121,686 3 Claims. (Cl. 141-1) This invention pertains to a process and apparatus for filling and for removing contaminants from a flotation instrument. More particularly this invention is adapted to remove contaminants and gases from the flotation fluid within the flotation chamber of flotation gyroscopes, distance meters, velocity meters, accelerometers, or the like.

Prior to this invention it was customary to remove dirt, chips, fluxes and other material from the flotation chamber of a flotation instrument by flushing the flotation chamber with Freon, tri-chlor-ethylene, or other suitable solvent. It was then necessary to remove the solvent by flushing the flotation chamber with a neutralizing liquid. If the solvent was not chemically neutralized, the residue would corrode the walls of the flotation chamber. Further, the light solvent did not physically remove chips and other contaminants from the flotation chamber.

Prior to this invention it was considered necessary to outgas or remove gases from the flotation chamber by pulling a vacuum on the chamber. However, because of the relative'length of the pumping path compared to the area of the exit opening of the flotation chamber, gases were notefliciently removed from the flotation chamber.

Prior to this invention it was considered necessary to fill the flotation chamber drop-by-drop with a dropper, both to avoid introducing air and to allow air to escape from the flotation chamber.

It has been discovered, in accordance with this invention, that the flotation fluid of the flotation instrument can be used to remove air and other contaminants from the flotation chamber. Examples of flotation fluids which are to support elements of a flotation instrument are fluorocarbons and silicones. One commonly used fluorocarbon has the trade name Flurolube. The flotation fluids are very dense which cause gases, fluxes, and particles to float or tend to float to the top of the liquid, thus helping to remove contaminants from the top of the instrument. The flotation fluids, it has been discovered, have an attraction for air and other gases. Thus the flotation fluid extracts the air or gas from the walls of the flotation chamber and other parts. The gas is then expelled with the flotation fluid from the top of the instrument.

It has further been discovered that the flotation fluid, when introduced with the process of this invention, is Any slight alkalinity or acidity is paratus used in this invention.

A bleed sump is attached to the conduit which carries the heavy eifluent, at the top of the instrument, to allow air or other gas to vent to the atmosphere. The eflluent is preferably filtered to remove particles, then returned to a storage tank. Fluid is pumped out of the storage tank into the bottom of the instrument by means of a squeeze-pump or constriction pump in which the pipe which carries the fluid is constricted to cause the fluid to be forced along the length of the pipe. The use of any other kind of known pump would introduce contaminants into the system. The fluid preferably is filtered again between the storage tank and its entrance into the instrument case. During its wait in the storage tank, any re maining gases are allowed to escape from the fluid to the atmosphere.

Periodically samples of the eflluent from the instrument are extracted and a particle count is made to determine the quality of cleanliness within the instrument flotation chamber.

It is thus an object of this invention simultaneously to fill and to remove gases and other contaminants from the flotation chamber of a flotation instrument.

It is another object of this invention simultaneously to clean and fill an enclosed chamber.

It is a more particular object of this invention to use the flotation fluid of a flotation instrument to remove contaminants and gases from the flotation chamber of the instrument.

It is likewise a very particular object of this invention to describe a process or method which is adapted to achieve the above named objects.

It is another particular object of this invention to provide apparatus adapted to achieve the above enumerated objects Other objects will become apparent from the following description taken in connection with the accompanying single figure which shows apparatus adapted to be used to practice the process of this invention.

Referring to the figure, flotation instrument 10 is mounted upon a support frame 16 with its fill opening 12 at the bottom and its drain opening 14 at the top.

The piping used with this invention is preferably of the typeplastic pipe or the likewhich does not introduce contaminants. The valving, which preferably is used in this invention, is of the constrcition type. Typical constriction type valves are pinch valves 18, 20, 22, 24, and 26. It is to be noted that, to prevent contamination, no part of the valve contacts the circulating fluid.

The intake opening 12 is connected by pipes 28 and 30 to a storage tank 32 of flotation fluid. A filter is inserted into the pipe and a pressure gauge 36 is used to measure the head behind pump 38. Pump 38 is a constricted pump or squeeze-pump in which the moving parts of the pump do not contact the fluid within pipe 30.

In pump 38, pipe 30 lies in a groove 40. A rotating arm 42, mounted upon shaft 44 and driven by a prime mover or motor (not shown), causes pressure wheels 46 and 48 consecutively to contact pipe 30, constrictively to force fluid through pipe 30.

Pipe 50 is connected to be vented to the atmosphere through a bleed sump 52. Bleed sump 52 is partially filled with flotation fluid open to the atmosphere. Pipe 50 is also connected through pipes 53 and 54 and through filter 56 to storage tank 32.

A sample tap or pipe 58 is connected to pipe 53. The bottom end of pipe 58 is connected through a return pipe 60 and coupler 59 to storage tank 32.

In operation, valve 26 is closed. Pump 38 causes fluid to be forced through pipe 30, filter 34, and pipe 28 into the bottom opening 12 of instrument 10. It is to be noted that rather than using a pump 38, the liquid could, provided the walls of pipe 30 were sufliciently flexible, be forced by hand through pipe 30.

Fluid entering instrument 10 at opening 12 contacts the Walls and parts within the flotation chamber. The flotation fluid wets the surface of the walls and parts, attracts air and gas out of the spaces, floats contaminating substances and particles, and physically removes both contaminants and gases by physical motion of the flotation fluid out of drain 14. Gases within pipe 50 float to the top of the surface of the liquid in the sump 52, thence exhaust to the atmosphere. The fluid is circulated through pipes 53 and 54, through particle filter 56, to

storage tank 32. a

The fluid is continuouslycirculated through the flotation chamber of instrument 10 until it is believed that all significant contaminants and gases have been removed; When it is decided to sample the fluid in pipe 53 to dc termine the particle content of the fluid; pinch valve 24 is closed and valve 26 is opened which causes fluid 'to flow through pipe 58,-coupling59 and pipe 60 to storage tank 32. The flow, of fluidthrough pipe 58 cleans, pipe 58. Clamp 26 is then closed and, coupling'59 is removed.

Clamp 26; is then opened to remove a sample of fluid from pipe 58; The removed sample can'then conven- =ient1y be filtered by an external filter (not shown) to re move particles therefrom. Aparticle count canbe made on the sample as a quality control measure to determine the cleanliness of the interior of the flotation chamber of instrument 10.

If the instrument has an internal pump which is adapted I to prevent flotation fluid from entering certain portions of the instrument such asfor examplethe bearings .of-

the instrument, the internal pump preferably should be 1 A process'for removing contaminantsand for filling the flotationchamber of a flotation instrument comprising the steps of: circulating the flotation fluid into the bottom a'nd'out ofthe top of said chamber; bleeding gases out'of said fluid; and removing particlesifrom said fluid. V a V 2. A process for removing contaminants and gases started before the fluid is circulated to prevent fluid flow of the flotation fluid from forcing particles or other contaminants into the bearings. v

'Thus the process and apparatus-of thisinvention eliminatcs'the necessity of outgassing the flotation chamber by a vacuum technique. It also reduces corrosion problems.

Further the process of this invention is faster andmore eflicient both in removing contaminants andin filling the flotation chamber than any hitherto known process;

Although the process andapparatus of this invention has been described in detail it -is not intended that the invention should be limited to the above description but only in accordance with'the spirit and scope of the appended claims:

I claim:

' flotation; chamber and being adapted to use a flotation fluid in; said chamber; 'said' chamber having a flotation fluid fill opening and drain; said fill openingbeing positioned at theb'ottom and said drain at the top of said in strument; means forsqueeze-pumping said flotation fluid in a reacirculating manner'through flexible pipes into said fill'opening, through said chamber, .and out of said drain; means for removing gases and solid particles from said fluid in said pipes. V 3

References Cited by the Examiner t 1 UNITED STATES PATENTS 7 2,483,924" 10/49 Moulinier 103-149 2,653,420' 9/53 Ruth L a 134-169 2,665,772 1/54 Greer et al. 134- 169 2,945,515 7/60 Zimmerman 137-563 3,036,741 1 5/62 Hilts 222148 lsAVERNE D..GEIGER,:Prima ry Examiner. I EUGENE E. BLANCHARD, Examiner. 

1. A PROCESS FOR REMOVING CONTAMINANTS AND FOR FILLING THE FLOTATION CHAMBER FOR A FLOTATION INSTRUMENT COMPRISING THE STEPS OF: CIRCULATING THE FLOTATION FLUID INTO THE BOTTOM AND OUT OF THE TOP OF SAID CHAMBER; BLEEDING GASES OUT OF SAID FLUID; AND REMOVING PARTICLES FROM SAID FLUID. 